The National Electrical System (SEN) was restored this Thursday, although the investigation is still lacking to establish the conclusions regarding the reason for the outage of the Antonio Guiteras Thermoelectric Plant (CTE) of Matanzas, which in turn caused the disconnection, informed the Minister of Energy and Mines (Minem), Vicente de la O Levy, on the Round Table programme.

The phenomenon, described by him as the most unpleasant possible for any electricity operator, occurred in conditions of great weakness, due to which the risk of new disconnections continues latent, while the fragility of the system persists.

At the moment of the event, the Lidio Ramón Pérez CTE of Felton, Holguín, and a unit of the Carlos Manuel de Céspedes, located in Cienfuegos, were out of service. Furthermore, in recent days several floating power plants were withdrawn, which is why the West lost a lot of power due to floating generation, he specified.

However, he highlighted, the union of thousands of workers and directors of the sector, together with the accompaniment of various factors from each place with logistical, transportation and other support, made possible the restoration of the SEN in just over 28 hours.

That entire process responded to very rigorous restoration protocols and procedures, based on the analysis of the conditions regarding the networks and available units, assured Lázaro Guerra Hernández, Director of Electricity of Minem.

The event demonstrated, once again, the importance of microsystems for providing vital services and connecting with the CTEs, thanks to the work of the provincial dispatch centres and operators at all levels. Many people participated, without a particular protagonism, with a joint effort of a group of institutions, he highlighted.

For his part, Alfredo López Valdés, Director General of the UNE, also showed pride for the effort displayed. He mentioned the two fundamental problems of the SEN at present: the lack of maintenance and of frequency regulation.

He again announced the plans to carry out major maintenance on the Guiteras from the end of the year, for an approximate period of six months. Extensive work will be carried out on the boiler, although not a total transformation.

Among the actions, he alluded to a replacement of the reheater, which involves intervening with 15 kilometres of piping. They will also change regenerative heater baskets, burners, the economiser curves, low-pressure cylinders, bearings… Regarding the electrical component, he detailed, they will replace almost all the six-kilovolt bars and the 380-volt systems. Regarding regulation, they are acquiring four battery systems with 50 megawatts (MW) of power and an equal amount of MW per hour of accumulation each.

When problems arise, whose solution appears out of reach, they activate groups of experts, affirmed López Valdés. Meanwhile, several engineers were discussing these topics in China to look for alternatives.

Regarding the Eastern zone and the importance of the Felton CTE in the region, López Valdés commented that work on Block 2, which suffered a fire in 2022, has not ceased.

He specified that at this moment the country is making an effort that, if realised, could accelerate the times by two years, because the idea is “to never stop”.

He added that, in the case of Block 1 of the plant, a maintenance is being carried out for 20 days of cleaning the boiler, condenser and work is being done on many components, but “the most important work is inside the generator”.

López Valdés highlighted the importance of the Felton, Guiteras and Céspedes thermoelectric plants as basic machines of the System, and signified that work is being done without rest to improve the affectations.

On the other hand, the First Vice Minister, Argelio Jesús Abad Vigoa, explained that the SEN includes, besides the base in thermal generation, generation with gas, solar photovoltaic and distributed generation, the latter being a result of the vision of the Commander in Chief to confront this type of event and others.

He highlighted that without distributed generation it would have been very difficult to recover the System in this time, because it was what allowed maintaining vitality and giving energy to the plants to initiate the start-up and later the interconnection.

He commented that the country is developing a Government programme for the recovery of the SEN directed by the First Secretary of the Central Committee of the Party and President of the Republic, Miguel Díaz-Canel Bermúdez, and the prime minister, Manuel Marrero Cruz, in which the actions are checked weekly.

Furthermore, he affirmed that, as a result of this, 1 100 MW have been recovered to date, of which 976 MW were used in this event: 420 in fuel oil groups and 556 in diesel groups.

“Had we not worked on this recovery in these months, we would have had a more complex situation.”

WHAT IS BEING DONE TO STRENGTHEN THE SYSTEM?

Vicente de la O Levy specified that the Government Programme to gradually restore the SEN is broad and has the objective of achieving energy independence.

This, he said, begins with the production of fuel, which, although it presents a slight increase compared to the previous year, is not enough to supply all the thermoelectric plants that work with national crude oil.

For this, maintenance is needed on the deteriorated oil wells, the surface infrastructure, the valves, the pipelines and the tanks, which requires financial resources.

He explained that efforts are also concentrated on the production of gas, “which acts directly in electrical generation”.

As part of that strategy, which is for the medium and long term, and which requires producing with our own fuels, consumption through water, biomass, the sun, biofuels stands out, to thus achieve independence from imports from other countries.

Regarding the 30 synchronised solar photovoltaic parks, he specified that to date they have contributed more than 600 MW to the SEN.

“The photovoltaic zone is for renewable energy and has high levels of efficiency. Although the solar parks do not work the entire day, during the day it allows for not consuming so much fuel.”

He noted that energy accumulation is also incorporated into the Programme, and it will be easier to join with distributed generation: “We already have the energy accumulation to install 200 MW, which will stabilise the system”.

De la O Levy specified that, even if the solar photovoltaic parks were not installed, our National Electrical System already needed the batteries to stabilise it.

“How many trips, how many faults do we receive in our homes because the light goes and comes repeatedly due to variations that exist in the system?”, that is what is known as Automatic Frequency Tripping (AFT), he added.

“It is not that in the dispatch they are removing and putting it, that is automatic to protect and so that the system does not fall,” signified the Minister.

He detailed that in 2024 there were more than 500 trips due to the lack of regulation.

“Regulation is one of the most important elements that must exist in the SEN, and one of the most effective and efficient technologies to regulate is accumulation,” he recognised.

“Later will come another step of accumulation that is also already contracted, which is to deliver energy hour by hour to the system. There are countries that are already talking about solar photovoltaic energy 24 hours a day and already have it, and we are being one of the pioneering countries in penetration of solar photovoltaic energy with accumulation,” highlighted the head of Minem.

THE MAINTENANCE WORKS

The Minister of Energy and Mines specified that they will continue and finish the maintenance of the units Céspedes 4, East Havana 2 –which has a deep maintenance–, furthermore it is already online, Renté 5 which is also coming out of a significant intervention.

He added that they will intervene in Guiteras –although he did not specify the date–, and added that they continue intervening in Felton 2 and Felton 1 these days.

He clarified that, “dismantling the boiler that caught fire is an engineering work. That is not disassembling and scrapping, that requires engineering to dismantle it completely, the boiler dome, and that will continue, and work will continue on the thermoelectric plants as also part of the strategy.”

He recognised that the greatest strength this sector has is the workers. “The workers of the electrical sector do not need to be called, they are there and already know what needs to be done.

“Here there is no need to give orders, here what needs to be done are coordinations, because the system is very complex,” he expanded.